Skimmers for use in bodies of liquid such as swimming pools are known. U.S. Pat. No. 5,498,348, to the present applicants, references a number of skimmers from which the disclosure of U.S. Pat. No. 5,498,348 is distinguished by the vertical oscillation of the device when in use, thereby preventing a build up of debris at the inlet weirs of the device.
One problem with the device of U.S. Pat. No. 5,498,348 is that of the ballasting system employed. To achieve the desired vertical oscillation, the buoyancy elements of the device required significantly weighty ballasting located towards the periphery of each of the buoyancy elements. The ballasting was effected in practice by including a block of steel or other dense material conforming in part at least to the configuration of the hollow chambers forming the buoyancy elements.
The ballasts of the device disclosed in U.S. Pat. No. 5,498,348 were therefore fixed once enclosed in the sealed hollow chambers of the buoyancy elements and did not allow of buoyancy adjustment.
A further problem with the ballasting arrangement of U.S. Pat. No. 5,498,348 lay in the considerable weight of the assembled device making it awkward to manipulate and place in a body of liquid for use. Moreover, this additional weight of the ballasting increased considerably the cost of transport with the associated problems of packing and handling.
The combination of very different materials for the structure of the device which was of a lightweight injection moulded polymer, and the enclosed steel ballast formed a further disadvantage in respect of ease of recycling.
It is an object of the present invention to address or at least ameliorate some of the above disadvantages.
Notes
The term “comprising” (and grammatical variations thereof) is used in this specification in the inclusive sense of “having” or “including”, and not in the exclusive sense of “consisting only of”.
The above discussion of the prior art in the Background of the invention, is not an admission that any information discussed therein is citable prior art or part of the common general knowledge of persons skilled in the art in any country.